For vehicles with this light, it is located in the center of the instrument panel.

If your vehicle has the DURAMAX® 6.6L engine, this light will come on when the fuel filter needs to be changed. If your vehicle has the Isuzu 6H 7.8L L6 diesel engine, this light will come on when water is detected in the fuel system and when the fuel filter needs to be changed. See Fuel Filter Replacement and Water in Fuel for more information.